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Selective deboronation of the B6 vertex could be achieved by functionalizing the B3 vertex and the study conducted shows that same results are achieved by sterically masking the B3 vertex from the nucleophile. The compounds provide useful symmetrical intermediates for use as carboracycle and supramolecular precursors.

The reactions of nitrites with acrachno-4,6-C2B7H12- provide a general route to functionalized tricarbabecaboranyl anions, 6-R-nido-5,6,9-C3B7H9- containing a wide range of substituents. Also the reaction of these anions with (eta(super 5)-C5H5)Fe(CO)2I yields functionalized 1-(eta(super 5)-C5H5)-2-R-closo-1,2,3,4-FeC3B7H9 ferratricatbadecarnoranyl complexes, thus providing a pathway for the systematic tuning of their chemical and bioactivity properties.

The boron-atom insertion reaction of nido-9,11-I2-7,8-C2B9H92-, with the HBCl2:SMe2 complex yields closo4,7-I2-1,2-C2B10H10, 1, in excellent yield. Although the two boron atoms (B3 and B6) nearest to the carbon atoms in 1 are equally available for attack by nucleophiles, the boron-degradation reaction of 1 with alkoxide ion occurs only at the B6 vertex, yielding regioselectively [(CH3)3NH][nido-2,4-I2-7,8-C2B9H10], 2. The molecular structures of 1 and 2 have been determined by X-ray diffraction studies. Crystallographic data are as follows. For 1, monoclinic, space group P21/n, a = 6.9199(19) Å, b = 23.9560(7) Å, c = 7.2870(2) Å, β = 94.081(4)°, V = 1204.9(6) ų, Z = 4, ρcalcd = 2.18 g cm-3, R = 0.020, Rw = 0.0610; for 2, orthorhombic, space group Pca21, a = 14.1141(7) Å, b = 7.0276(4) Å, c = 16.4602(9) Å, v = 1632.7(15) ų, z = 4, ρcalcd = 1.81 gcm-3, R = 0.022, Rw = 0.0623. [ABSTRACT FROM AUTHOR]

The boron-atom insertion reaction of nido-9,11-I(2)-7,8-C(2)B(9)H(9)(2-), with the HBCl(2):SMe(2) complex yields closo-4,7-I(2)-1,2-C(2)B(10)H(10), 1, in excellent yield. Although the two boron atoms (B3 and B6) nearest to the carbon atoms in 1 are equally available for attack by nucleophiles, the boron-degradation reaction of 1 with alkoxide ion occurs only at the B6 vertex, yielding regioselectively [(CH(3))(3)NH][nido-2,4-I(2)-7,8-C(2)B(9)H(10)], 2. The molecular structures of 1 and 2 have been determined by X-ray diffraction studies. Crystallographic data are as follows. For 1, monoclinic, space group P2(1)/n, a = 6.9199(19) Angstroms, b = 23.9560(7) Angstroms, c = 7.2870(2) Angstroms, beta = 94.081(4) degrees, V = 1204.9(6) Angstroms(3), Z = 4, rho(calcd) = 2.18 g cm(-3), R = 0.020, R(w) = 0.0610; for 2, orthorhombic, space group Pca2(1), a = 14.1141(7) Angstroms, b = 7.0276(4) Angstroms, c = 16.4602(9) Angstroms, V = 1632.7(15) Angstroms(3), Z = 4, rho(calcd) = 1.81 gcm(-3), R = 0.022, R(w) = 0.0623.